Add tap() into ShallowWrapper and ReactWrapper

docs/api/ReactWrapper/tap.md

@@ -0,0 +1,33 @@
+# `.tap(intercepter) => Self`
+
+Invokes intercepter and returns itself. intercepter is called with itself.
+This is helpful when debugging nodes in method chains.
+
+#### Arguments
+
+1. `intercepter` (`Self`): the current ReactWrapper instance.
+
+
+
+#### Returns
+
+`Self`: the current ReactWrapper instance.
+
+
+
+#### Example
+
+
+```jsx
+const result = mount(
+  <ul>
+    <li>xxx</li>
+    <li>yyy</li>
+    <li>zzz</li>
+  </ul>
+)
+.find('li')
+.tap(n => console.log(n.debug()))
+.map(n => n.text())
+;
+```

docs/api/ShallowWrapper/tap.md

@@ -0,0 +1,33 @@
+# `.tap(intercepter) => Self`
+
+Invokes intercepter and returns itself. intercepter is called with itself.
+This is helpful when debugging nodes in method chains.
+
+#### Arguments
+
+1. `intercepter` (`Self`): the current ShallowWrapper instance.
+
+
+
+#### Returns
+
+`Self`: the current ShallowWrapper instance.
+
+
+
+#### Example
+
+
+```jsx
+const result = shallow(
+  <ul>
+    <li>xxx</li>
+    <li>yyy</li>
+    <li>zzz</li>
+  </ul>
+)
+.find('li')
+.tap(n => console.log(n.debug()))
+.map(n => n.text())
+;
+```

src/ReactWrapper.js

@@ -733,6 +733,17 @@ export default class ReactWrapper {
     return debugInsts(this.nodes);
   }
 
+  /**
+   * Invokes intercepter and returns itself. intercepter is called with itself.
+   * This is helpful when debugging nodes in method chains.
+   * @param fn
+   * @returns {ReactWrapper}
+   */
+  tap(intercepter) {
+    intercepter(this);
+    return this;
+  }
+
   /**
    * Detaches the react tree from the DOM. Runs `ReactDOM.unmountComponentAtNode()` under the hood.
    *

src/ShallowWrapper.js

@@ -721,4 +721,15 @@ export default class ShallowWrapper {
   debug() {
     return debugNodes(this.nodes);
   }
+
+  /**
+   * Invokes intercepter and returns itself. intercepter is called with itself.
+   * This is helpful when debugging nodes in method chains.
+   * @param fn
+   * @returns {ShallowWrapper}
+   */
+  tap(intercepter) {
+    intercepter(this);
+    return this;
+  }
 }

test/ReactWrapper-spec.js

@@ -1764,6 +1764,22 @@ describeWithDOM('mount', () => {
     });
   });
 
+  describe('.tap()', () => {
+    it('should call the passed function with current ShallowWrapper and returns itself', () => {
+      const spy = sinon.spy();
+      const wrapper = mount(
+        <ul>
+          <li>xxx</li>
+          <li>yyy</li>
+          <li>zzz</li>
+        </ul>
+      ).find('li');
+      const result = wrapper.tap(spy);
+      expect(spy.calledWith(wrapper)).to.equal(true);
+      expect(result).to.equal(wrapper);
+    });
+  });
+
   describe('attachTo option', () => {
     it('should attach and stuff', () => {
       class Foo extends React.Component {

test/ShallowWrapper-spec.js

@@ -2198,4 +2198,21 @@ describe('shallow', () => {
     expect(rendered.length).to.equal(0);
     expect(rendered.html()).to.equal(null);
   });
+
+  describe('.tap()', () => {
+    it('should call the passed function with current ShallowWrapper and returns itself', () => {
+      const spy = sinon.spy();
+      const wrapper = shallow(
+        <ul>
+          <li>xxx</li>
+          <li>yyy</li>
+          <li>zzz</li>
+        </ul>
+      ).find('li');
+      const result = wrapper.tap(spy);
+      expect(spy.calledWith(wrapper)).to.equal(true);
+      expect(result).to.equal(wrapper);
+    });
+  });
+
 });